How can I make Perl wait for child processes started in the background with system()?

Question

I have some Perl code that executes a shell script for multiple parameters, to simplify, I\'ll just assume that I have code that looks like this:

for $p (@a){
           


        

Answer 1

Using fork/exec/wait isn't so bad:

my @a = (1, 2, 3);
for my $p (@a) {
   my $pid = fork();
   if ($pid == -1) {
       die;
   } elsif ($pid == 0) {
      exec '/bin/sleep', $p or die;
   }
}
while (wait() != -1) {}
print "Done\n";